62 CLASS XIV. 



have been regarded incorrectly as distinct species. See a figure in 

 Lacepede Foiss. I. PL vii. fig. 1. 



Many species have spines or tubercles on the back, on the fins 

 and the tail, which vary in number and development according to 

 age and difiei'ence of sex. 



A. Tail slender. Body discoldal, hroad. 

 f A serrated spur at the base of tail. 



Ce2)]ialo2-)tera DuMER. {Pterocephala SwAlNS.). Pectoral fins 

 very broad, acuminate towards the point, produced in front of the 

 liead like ears. Teeth small. 



Sp. Cephaloptera Giorna Risso, Eaja giorna Lac, PoIss. v. PI. 20, fig. 3, 

 GuERiN Iconogr., Poiss. PI. 69, fig. 4 ; attains a breadth of more than 4 

 feet ; this species occurs in the Mediterranean, but species from the East 

 Indies, Japan and Brazil are also known. 



Ceratoj^tera Muell. and Henle. 



Myliohatis Cuv. Pectoral fins broad, acuminate towards the 

 apex, interrupted at the sides of head, surrounding the head an- 

 teriorly. Teeth large, composed of vertical fibres or cylinders, 

 forming transverse flat lamince, covering each jaw with mosaic 

 work. Tail flagelliform, very long, armed with a serrated spur 

 behind the dorsal fin. 



Sp. Mylidbatis aguUa Risso, Raja aguila L., Yaeeell Brit. Fishes, 11. 

 p. 445, Mediten-anean Sea, &c. 



Sub-genera: Ehinoptera Kuhl, Aetobatis Muell. and Henle. 



Sp. Aetobatis flagellum, Raja flagellum. Bloch Syst. Ichth. Tab. 73, habit, in 

 Indian Sea, &c. 



Trygon Adans. Pectoral fins surrounding the head and often 

 produced into a point in front of head. Disc of body oval, or- 

 bicular or obtusely rhombic. Teeth placed in alternate rows, 

 rhombic. Tail mostly of length of body, without finlets, furnished 

 with single or double serrate aculeus. 



Add genera Urolophus and Trygonoptera Muell. and Henle. 



Anacanthus Ehrenb. A genus allied to the Trygons, distin- 

 guished by defect of spur in the tail. 



Sp. Trygon jyasfinacea BoNAP., Raja pastinacea Li., Bloch Ichth. Tab. 82, 

 C. L. Bonaparte Fauna Italica, 1841, in. Tab. 156; in the Mediter- 

 ranean and North Sea, &c. 



